Significant effect of time (p<10−4) and group (p<10−4) with significant interaction between the two factors (p<10−4) on 15N NIA in liver, muscle and fur. a) * P<0.05 between NPD in gestation and LPD in gestation, ** P<0.05 15N NIA higher in the NPD/NPD and LPD/NPD groups than in the LPD/LPD and NPD/LPD groups, *** P<0.05 In all groups, d30 15N NIA increased up to d60 † and decreased afterwards (d480). b) *P<0.05 between both NPD/NPD—LPD/NPD groups and LPD/LPD—NPD/LPD groups. c) *P<0.05 between both NPD/NPD—LPD/NPD groups and LPD/LPD—NPD/LPD groups. **P<0.05 between NPD/NPD group and the other three diet, ***P<0.05 NPD/NPD and LPD/NPD groups had higher 15N NIA values, † P<0.05 between the LPD/NPD and the NPD/NPD groups, †† P<0.05 between d11-d30 and d480 in the LPD/NPD group. Diet groups: gestation/lactation. LPD: low protein diet (10% protein, isocaloric), NPD: normal protein diet (22% protein). NPD/NPD group: d1: n = 14, d11: n = 26, d30: n = 10, d60: n = 17, d480: n = 4; LPD/NPD group: d1: n = 12, d11: n = 17, d30: n = 6, d60: n = 4, d480: n = 7; LPD/LPD group: d1: n = 15, d11: n = 10, d30: n = 6, d60: n = 11, d480: n = 6; and NPD/LPD group: d1: n = 16, d11: n = 11, d30: n = 8, d60: n = 8, d480: n = 8.